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Problem
Problem
If
f
(
x
)
f(x)
f
(
x
)
is a decreasing function and attain positive values, then the set of value of '
k
k
k
', for which the major axis of the ellipse
x
2
f
(
k
2
+
2
k
+
5
)
+
y
2
f
(
k
+
1
)
=
1
\frac{x^2}{f(k^2 + 2k + 5)} + \frac{y^2}{f(k + 1)} = 1
f
(
k
2
+
2
k
+
5
)
x
2
+
f
(
k
+
1
)
y
2
=
1
, is the
X
X
X
-axis, is
(
−
a
,
b
)
(-a, b)
(
−
a
,
b
)
, then
(
a
+
b
)
(a+b)
(
a
+
b
)
is
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